Field of the Invention
An aspect of the described technology generally relates to a linear evaporation source and a deposition apparatus having the same.
Description of the Related Art
Flat panel displays have replaced cathode ray tube displays mainly due to their light weight and thin profile. Typical examples of such displays include liquid crystal displays (LCDs) and organic light emitting diode displays (OLEDs). In comparison with LCDs, OLEDs generally have better luminance and viewing angle characteristics, and require no backlight, so that they can be realized as ultra thin displays.
These OLEDs display images using a phenomenon whereby electrons and holes that are injected into an organic thin film through a cathode and an anode are recombined to form excitons. Thus, light having a specific wavelength is emitted by the release of energy resulting from de-excitation of the excitons.
OLEDs are manufactured by a photolithography method or a deposition method to selectively form a cathode, an anode, and an organic thin film on a substrate formed of glass, stainless steel, or synthetic resin. In the deposition method, a deposition material is evaporated or sublimated, deposited under vacuum, and selectively etched, or a deposition material is selectively deposited using a mask assembly having a plurality of slits in a predetermined pattern.
Here, the photolithography method generally calls for applying photoresist to a predetermined region, and then performing wet- or dry-etching on the applied photoresist. In the process of removing or etching the photoresist, moisture may penetrate into the underlying substrate. For materials which degrade in the presence of moisture, such as an organic thin film, deposition is the primary method used to form a thin film.